Exemplary display devices usually are controlled based on active switches and have numerous advantages such as thin body, energy saving and radiation-free and thus have been widely used. The display devices primarily include liquid crystal display devices, OLED (Organic Light-Emitting Diode) display devices, QLED (Quantum Dot Light Emitting Diodes) display devices, plasma display devices and so on, and in terms of appearance structures, they may be flat-type display devices and/or curved-type display devices.
As to the liquid crystal display device, it includes two parts such as a liquid crystal panel and a backlight module. A working principle of the liquid crystal display device is disposing liquid crystal molecules between two parallel glass substrates and applying a driving voltage onto the two glass substrate to control rotation directions of the liquid crystal molecules to refract light rays from the backlight module and thereby produce an image.
With regard to the OLED display device, it uses the self-luminous organic light emitting diodes to achieve a display and has advantages of self-luminous, wide viewing angle, almost infinite high contrast, low power consumption, high response speed and so on.
The QLED display device has a structure very similar to that of the OLED and a main difference is that a luminescent center of the QLED consists of quantum dots. Electrons and holes at two sides of the structure will combine in a quantum dot layer to form excitons and thereby emit light through recombination of the excitons.
With the developments of display devices gradually aiming at super-size, high driving frequency, high resolution and other aspects, a TFT structure is often an inverted staggered structure, that is, a gate electrode is at the bottom and source/drain electrodes are respectively located on both sides of an α-Si layer. As to such device structure, in on aspect, because the AS (active semiconductor) tail is excessively long, it will produce a leakage current, resulting in neither safe nor energy saving and also being adverse to normal operation of equipment; and in another aspect, often due to excessively small line width of the source/drain electrode layers after etching treatments, there may be a risk of line broken.